1. Field of the Invention
The present invention relates to a head suspension for a hard disk drive installed in an information processing apparatus such as a computer.
2. Description of Related Art
FIG. 26 is a perspective view showing a head suspension for a hard disk drive according to a related art. The head suspension 201 has a one-piece structure including a base plate 203 and a load beam 205 that are integrated into one piece to support a flexure 207. The load beam 205 includes a rigid part (or stiff part) 209 and a resilient part (or hinge) 211.
FIG. 27 is a sectional view partly showing an example of the hard disk drive in which the head suspension 201 of FIG. 26 is arranged. The base plate 203 of the head suspension 201 is attached to a disk-side surface of an arm 215 by, for example, swaging. The arm 215 is attached to a carriage 213.
The carriage 213 is turned around a spindle 219 by a positioning motor 217 such as a voice coil motor. By turning the carriage 213 around the spindle 219, a head 221 of the head suspension 201 is moved to a target track on a disk 223.
When the disk 223 is rotated at high speed, the head 221 slightly lifts from the surface of the disk 223 against a gram load that is a load applied to the head 221 by the head suspension 201.
In recent years, portable music players and the like employ one-inch hard disk drives. For the use with such instruments and cellular phones, miniaturized hard disk drives such as 0.85-inch and 1-inch hard disk drives are intensely developed.
The miniaturized hard disk drives for the cellular phones and the like must have not only improved environmental resistance, antishock ability, and low power consumption but also thinness thinner than the appliances themselves.
According to the structure of the related art shown in FIGS. 26 and 27, the thicknesses of the arm 215, load beam 205, flexure 207, and head 221 are added to the thickness of the disk 223. The total thickness from the arm 215 to the head 221 is difficult to reduce, and therefore, it is not easy to thin the hard disk drive.
The arm 215 and load beam 205 involves a step with respect to the disk 223. Namely, there is a difference between the center of gravity of the arm 215 and that of the load beam 205 with respect to the disk 223. Due to this difference, the arm 215 is vulnerable to torsional motion and is limited in a shock property.
The step between the arm 215 and the load beam 205 must be reduced.
Reducing the step between the arm 215 and the load beam 205, however, results in bringing the flexure 207 closer to the disk 223, particularly on the arm 215 side.
The related art mentioned above is disclosed in Japanese Unexamined Patent Application Publication No. 09-282624.